[Mesa-dev] [PATCH 1/4] i965/fs: Add stub lowering pass for logical send-message opcodes.

[Francisco Jerez]

This pass will house ad-hoc lowering code for several send
message-like virtual opcodes that will represent their logically
independent arguments as separate instruction sources rather than as a
single payload blob.  This pass will basically just take the separate
arguments that are supposed to be part of the payload and concatenate
them to construct a message in the form required by the hardware.
Virtual instructions in separate-source form will eventually allow
some simplification of the visitor code and make several
transformations easier like lowering SIMD16 instructions to SIMD8
algorithmically in cases where the hardware doesn't support the former
natively.
---
 src/mesa/drivers/dri/i965/brw_fs.cpp | 29 ++++++++++++++++++++++++++++-
 src/mesa/drivers/dri/i965/brw_fs.h   |  1 +
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 2e835b1..09ff587 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3179,6 +3179,30 @@ fs_visitor::lower_integer_multiplication()
    return progress;
 }
 
+bool
+fs_visitor::lower_logical_sends()
+{
+   bool progress = false;
+
+   foreach_block_and_inst_safe(block, fs_inst, inst, cfg) {
+      const fs_builder ibld = bld.exec_all(inst->force_writemask_all)
+                                 .group(inst->exec_size, inst->force_sechalf)
+                                 .at(block, inst);
+
+      switch (inst->opcode) {
+      default:
+         continue;
+      }
+
+      progress = true;
+   }
+
+   if (progress)
+      invalidate_live_intervals();
+
+   return progress;
+}
+
 void
 fs_visitor::dump_instructions()
 {
@@ -3626,9 +3650,12 @@ fs_visitor::optimize()
       backend_shader::dump_instructions(filename);
    }
 
-   bool progress;
+   bool progress = false;
    int iteration = 0;
    int pass_num = 0;
+
+   OPT(lower_logical_sends);
+
    do {
       progress = false;
       pass_num = 0;
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index c005666..f3850d1 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -182,6 +182,7 @@ public:
    void no16(const char *msg);
    void lower_uniform_pull_constant_loads();
    bool lower_load_payload();
+   bool lower_logical_sends();
    bool lower_integer_multiplication();
    bool opt_combine_constants();
 
-- 
2.4.3